Gesellschaft fur anilin fabrikation



UNITED STATES PATENT -EEIcE.

RICHARD KIRCHHOFF, OF BERLIN, GERMANY, ASSIGNOR TO THE ACTIEN=GESELLSOHAFT FUR ANILIN FABRIKATIONOF SAME PLACE.

BLUE DYE.

SPECIFICATION forming part of Letters Patent No. 536,880, dated AprilApplication filed November 10, 1894. serial No. 528,448. (Specimens) .TO00% whom 712'; may concern:

Be it known that I, RICHARD KIROHHOFF, of Berlin, in the Kingdom ofPrussia, German Empire, have invented new and useful Improvements in theProduction of a Blue Dye; and I do hereby declare that the following isa full, clear, and exact description ofthe invention, which will enableothers skilled in the art to which it appertains to make and use thesame.

This invention relates to the production of new tetrazo dye whichproduces on unmordanted cotton fast blue shades.

The new coloring matter is produced by re acting with two molecules ofgamma-amidonaphtolmonosulfo acid in weakly acid solution upon onemolecule of tetrazotized paraamidobenzene-azo-amido-para-cresolether.

The aforementioned diamido base may be obtained by combiningpara-nitro-diazobenzone with amido-para-cresolether and red ucing thenitro-amido-azo-compound by means of alkali sulfides. The base derivedin this way for instance from para-amido-cresolmethylether (OH :OGH :NH:1:4:3) forms in dry state a yellowish brown powder, easily soluble inalcohol or benzene with a yellow color, melting at 115 centigrade. It issoluble in diluted hydrochloric acid with deep-red color. Thepreparation of the new dye derived from this base may' be practicallycarried out in the following manner: Twenty-five and onehalf kilogramsof para-amidobenzene-azoamido-para-cresolmethylether or the corresponding quantity of its sulfate or hydrochlorate and sixty kilograms ofhydrochloric acid are dissolved in water and diazotized in the Wellknown manner by means of fourteen kilograms of sodium nitrite. Thediazo-body, which forms a yellow-brown solution is added to a solutionof fifty-three kilograms of the sodium salt ofgamma-amidonaphtolmonosulfo acid in presence of an excess of sodiumacetate. The coloring matter separates in the shape of a violet-blackpowder. After stirring for some hours the solution is gently heated andmade alkaline and the dye-stuff is precipitated by means of common salt.It dyes unmordanted cotton blue shades, fast to acid, alkali and light.

The coloring matter in dry state is a black brown powder with metallicluster, soluble in cold more readily in hot water, with violet bluecolor, which is not altered by the addition of caustic soda lye, anexcess of the lye producing a black-violet precipitate.

In alcohol or ether the dye is practically insoluble.

From the aqueous solution of the dye the free color-acid is immediatelyprecipitated if mineral acids'are added, while on addition of aceticacid the separation is imperfect. 7

Concentrated sulfuric acid dissolves the coloring matter with blue blackcolor, which on diluting with water turns at first violet, but onfurther diluting the free color acid separates in the shape ofblack-violet flakes.

Having now described my invention, what I claim is The hereinbeforedescribed dye produced by combining one molecule ofpara-amidobenzene-azo-amido-para-cresolether with two molecules ofgamma-amidonaphtolmonosulfo acid in weakly acid solution said dyepossessing the following constitution formula 011 1 06H, 0.A1k(4) OH(S)1 N:NO,OH4 NH2(2) N sonwe u y N 011(8) NH, 2 'SO Na. (6)

being soluble in cold more readily in hot Water with violet blue color,which is not altered by the addition of caustic soda lye, practicallyinsoluble in alcohol and ether, soluble in concentrated sulfuric acidwith blue black color, which on diluting with water turns at firstviolet While on further diluting the free color acid separates in theshape of black violet fiakes, said dyeproducing on unmordanted cottonfast blue shades.

In testimony whereof I hereunto set my hand and affix my seal, in thepresence of two Witnesses, this 26th day of October, A. D. 1894.

RICHARD KIRCHHOFF. [L.s.]

Witnesses:

RUDOLF VON ROTZENBURG, GUsTAv Loom.

